1. Field of the Invention
This invention relates to electrically conductive coated surfaces. More specifically, it refers to a permanently solderable palladium-nickel alloy coating on an electrically conductive substrate.
2. Description of the Prior Art
Gold platings are commonly used to protect electrical contacts from corrosion and at the same time maintain solderability properties and low electrical contact resistance at low loads. Unfortunately, gold platings are extremely expensive. Lower cost substitutes have been sought such as palladium-nickel alloys. A typical method of forming a palladium-nickel alloy on an electrically conductive substrate is set forth in U.S. Pat. No. 4,100,039. While known palladium nickel alloys provide a less expensive corrosion-resistant layer, they suffer from reduced solderability properties and increased electrical contact resistance at low normal loads.